diff --git a/fuzz/Cargo.lock b/fuzz/Cargo.lock
index edf650e3..06300fd2 100644
--- a/fuzz/Cargo.lock
+++ b/fuzz/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "adler"
@@ -116,6 +116,31 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
 
+[[package]]
+name = "bon"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a636f83af97c6946f3f5cf5c268ec02375bf5efd371110292dfd57961f57a509"
+dependencies = [
+ "bon-macros",
+ "rustversion",
+]
+
+[[package]]
+name = "bon-macros"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7eaf1bfaa5b8d512abfd36d0c432591fef139d3de9ee54f1f839ea109d70d33"
+dependencies = [
+ "darling",
+ "ident_case",
+ "prettyplease",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.16.0"
@@ -198,12 +223,12 @@ checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
 
 [[package]]
 name = "comrak"
-version = "0.29.0"
+version = "0.30.0"
 dependencies = [
  "arbitrary",
+ "bon",
  "caseless",
  "clap",
- "derive_builder",
  "emojis",
  "entities",
  "memchr",
@@ -237,9 +262,9 @@ dependencies = [
 
 [[package]]
 name = "darling"
-version = "0.20.9"
+version = "0.20.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "83b2eb4d90d12bdda5ed17de686c2acb4c57914f8f921b8da7e112b5a36f3fe1"
+checksum = "6f63b86c8a8826a49b8c21f08a2d07338eec8d900540f8630dc76284be802989"
 dependencies = [
  "darling_core",
  "darling_macro",
@@ -247,9 +272,9 @@ dependencies = [
 
 [[package]]
 name = "darling_core"
-version = "0.20.9"
+version = "0.20.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "622687fe0bac72a04e5599029151f5796111b90f1baaa9b544d807a5e31cd120"
+checksum = "95133861a8032aaea082871032f5815eb9e98cef03fa916ab4500513994df9e5"
 dependencies = [
  "fnv",
  "ident_case",
@@ -261,9 +286,9 @@ dependencies = [
 
 [[package]]
 name = "darling_macro"
-version = "0.20.9"
+version = "0.20.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "733cabb43482b1a1b53eee8583c2b9e8684d592215ea83efd305dd31bc2f0178"
+checksum = "d336a2a514f6ccccaa3e09b02d41d35330c07ddf03a62165fcec10bb561c7806"
 dependencies = [
  "darling_core",
  "quote",
@@ -290,37 +315,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "derive_builder"
-version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0350b5cb0331628a5916d6c5c0b72e97393b8b6b03b47a9284f4e7f5a405ffd7"
-dependencies = [
- "derive_builder_macro",
-]
-
-[[package]]
-name = "derive_builder_core"
-version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d48cda787f839151732d396ac69e3473923d54312c070ee21e9effcaa8ca0b1d"
-dependencies = [
- "darling",
- "proc-macro2",
- "quote",
- "syn",
-]
-
-[[package]]
-name = "derive_builder_macro"
-version = "0.20.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "206868b8242f27cecce124c19fd88157fbd0dd334df2587f36417bafbc85097b"
-dependencies = [
- "derive_builder_core",
- "syn",
-]
-
 [[package]]
 name = "deunicode"
 version = "1.4.4"
@@ -561,11 +555,21 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
 
+[[package]]
+name = "prettyplease"
+version = "0.2.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "64d1ec885c64d0457d564db4ec299b2dae3f9c02808b8ad9c3a089c591b18033"
+dependencies = [
+ "proc-macro2",
+ "syn",
+]
+
 [[package]]
 name = "proc-macro2"
-version = "1.0.81"
+version = "1.0.92"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3d1597b0c024618f09a9c3b8655b7e430397a36d23fdafec26d6965e9eec3eba"
+checksum = "37d3544b3f2748c54e147655edb5025752e2303145b5aefb3c3ea2c78b973bb0"
 dependencies = [
  "unicode-ident",
 ]
@@ -630,6 +634,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e819f2bc632f285be6d7cd36e25940d45b2391dd6d9b939e79de557f7014248"
+
 [[package]]
 name = "ryu"
 version = "1.0.17"
@@ -706,9 +716,9 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
 [[package]]
 name = "syn"
-version = "2.0.60"
+version = "2.0.89"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "909518bc7b1c9b779f1bbf07f2929d35af9f0f37e47c6e9ef7f9dddc1e1821f3"
+checksum = "44d46482f1c1c87acd84dea20c1bf5ebff4c757009ed6bf19cfd36fb10e92c4e"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/script/cibuild b/script/cibuild
index 794441cc..64016bb7 100755
--- a/script/cibuild
+++ b/script/cibuild
@@ -48,6 +48,8 @@ python3 spec_tests.py --no-normalize --spec ../../../src/tests/fixtures/wikilink
   || failed=1
 python3 spec_tests.py --no-normalize --spec ../../../src/tests/fixtures/wikilinks_title_before_pipe.md "$PROGRAM_ARG -e wikilinks-title-before-pipe" \
   || failed=1
+python3 spec_tests.py --no-normalize --spec ../../../src/tests/fixtures/description_lists.md "$PROGRAM_ARG -e description-lists" \
+  || failed=1
 
 python3 spec_tests.py --no-normalize --spec regression.txt "$PROGRAM_ARG" \
 	|| failed=1
diff --git a/src/html.rs b/src/html.rs
index eb542c5d..0d633c6b 100644
--- a/src/html.rs
+++ b/src/html.rs
@@ -479,7 +479,7 @@ impl<'o> HtmlFormatter<'o> {
                     self.cr()?;
                     self.output.write_all(b"<dl")?;
                     self.render_sourcepos(node)?;
-                    self.output.write_all(b">")?;
+                    self.output.write_all(b">\n")?;
                 } else {
                     self.output.write_all(b"</dl>\n")?;
                 }
@@ -663,6 +663,7 @@ impl<'o> HtmlFormatter<'o> {
                     .map(|n| n.data.borrow().value.clone())
                 {
                     Some(NodeValue::List(nl)) => nl.tight,
+                    Some(NodeValue::DescriptionItem(nd)) => nd.tight,
                     _ => false,
                 };
 
diff --git a/src/nodes.rs b/src/nodes.rs
index ec6e549c..85407a7a 100644
--- a/src/nodes.rs
+++ b/src/nodes.rs
@@ -313,6 +313,10 @@ pub struct NodeDescriptionItem {
 
     /// Number of characters between the start of the list marker and the item text (including the list marker(s)).
     pub padding: usize,
+
+    /// Whether the list is [tight](https://github.github.com/gfm/#tight), i.e. whether the
+    /// paragraphs are wrapped in `<p>` tags when formatted as HTML.
+    pub tight: bool,
 }
 
 /// The type of list.
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index e08fdc01..2c233981 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -334,7 +334,7 @@ pub struct ExtensionOptions {
     /// let mut options = Options::default();
     /// options.extension.description_lists = true;
     /// assert_eq!(markdown_to_html("Term\n\n: Definition", &options),
-    ///            "<dl><dt>Term</dt>\n<dd>\n<p>Definition</p>\n</dd>\n</dl>\n");
+    ///            "<dl>\n<dt>Term</dt>\n<dd>\n<p>Definition</p>\n</dd>\n</dl>\n");
     /// ```
     #[builder(default)]
     pub description_lists: bool,
@@ -1636,10 +1636,13 @@ impl<'a, 'o> Parser<'a, 'o> {
                 container.data.borrow_mut().internal_offset = matched;
             } else if !indented
                 && self.options.extension.description_lists
-                && line[self.first_nonspace] == b':'
-                && self.parse_desc_list_details(container)
+                && unwrap_into(
+                    scanners::description_item_start(&line[self.first_nonspace..]),
+                    &mut matched,
+                )
+                && self.parse_desc_list_details(container, matched)
             {
-                let offset = self.first_nonspace + 1 - self.offset;
+                let offset = self.first_nonspace + matched - self.offset;
                 self.advance_offset(line, offset, false);
                 if strings::is_space_or_tab(line[self.offset]) {
                     self.advance_offset(line, 1, true);
@@ -1881,10 +1884,28 @@ impl<'a, 'o> Parser<'a, 'o> {
         }
     }
 
-    fn parse_desc_list_details(&mut self, container: &mut &'a AstNode<'a>) -> bool {
+    fn parse_desc_list_details(&mut self, container: &mut &'a AstNode<'a>, matched: usize) -> bool {
+        let mut tight = false;
         let last_child = match container.last_child() {
             Some(lc) => lc,
-            None => return false,
+            None => {
+                // Happens when the detail line is directly after the term,
+                // without a blank line between.
+                if !node_matches!(container, NodeValue::Paragraph) {
+                    // If the container is not a paragraph, then this can't
+                    // be a description list item.
+                    return false;
+                }
+
+                let parent = container.parent();
+                if parent.is_none() {
+                    return false;
+                }
+
+                tight = true;
+                *container = parent.unwrap();
+                container.last_child().unwrap()
+            }
         };
 
         if node_matches!(last_child, NodeValue::Paragraph) {
@@ -1908,7 +1929,7 @@ impl<'a, 'o> Parser<'a, 'o> {
             //   All are incorrect; they all give the start line/col of
             //   the DescriptionDetails, and the end line/col is completely off.
             //
-            // descriptionDetails:
+            // DescriptionDetails:
             //   Same as the DescriptionItem.  All but last, the end line/col
             //   is (l+1):0.
             //
@@ -1931,7 +1952,8 @@ impl<'a, 'o> Parser<'a, 'o> {
 
             let metadata = NodeDescriptionItem {
                 marker_offset: self.indent,
-                padding: 2,
+                padding: matched,
+                tight,
             };
 
             let item = self.add_child(
@@ -1948,6 +1970,31 @@ impl<'a, 'o> Parser<'a, 'o> {
 
             *container = details;
 
+            true
+        } else if node_matches!(last_child, NodeValue::DescriptionItem(..)) {
+            let parent = last_child.parent().unwrap();
+            let tight = match last_child.data.borrow().value {
+                NodeValue::DescriptionItem(ref ndi) => ndi.tight,
+                _ => false,
+            };
+
+            let metadata = NodeDescriptionItem {
+                marker_offset: self.indent,
+                padding: matched,
+                tight,
+            };
+
+            let item = self.add_child(
+                parent,
+                NodeValue::DescriptionItem(metadata),
+                self.first_nonspace + 1,
+            );
+
+            let details =
+                self.add_child(item, NodeValue::DescriptionDetails, self.first_nonspace + 1);
+
+            *container = details;
+
             true
         } else {
             false
diff --git a/src/scanners.re b/src/scanners.re
index 35bbc4f6..f665f854 100644
--- a/src/scanners.re
+++ b/src/scanners.re
@@ -431,4 +431,13 @@ pub fn tasklist(s: &[u8]) -> Option<(usize, u8)> {
 */
 }
 
+pub fn description_item_start(s: &[u8]) -> Option<usize> {
+    let mut cursor = 0;
+    let len = s.len();
+/*!re2c
+    [:~] ([ \t]+) { return Some(cursor); }
+    * { return None; }
+*/
+}
+
 // vim: set ft=rust:
diff --git a/src/scanners.rs b/src/scanners.rs
index 52b2a747..29eca63b 100644
--- a/src/scanners.rs
+++ b/src/scanners.rs
@@ -1,4 +1,4 @@
-/* Generated by re2c 3.1 */
+/* Generated by re2rust 4.0 */
 
 pub fn atx_heading_start(s: &[u8]) -> Option<usize> {
     let mut cursor = 0;
@@ -246,9 +246,7 @@ pub fn atx_heading_start(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -2065,9 +2063,7 @@ pub fn html_block_end_1(s: &[u8]) -> bool {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -2747,9 +2743,7 @@ pub fn html_block_end_2(s: &[u8]) -> bool {
                 25 => {
                     return true;
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -3369,9 +3363,7 @@ pub fn html_block_end_3(s: &[u8]) -> bool {
                 24 => {
                     return true;
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -3900,9 +3892,7 @@ pub fn html_block_end_4(s: &[u8]) -> bool {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -4582,9 +4572,7 @@ pub fn html_block_end_5(s: &[u8]) -> bool {
                 25 => {
                     return true;
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -5280,9 +5268,7 @@ pub fn open_code_fence(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -5544,9 +5530,7 @@ pub fn close_code_fence(s: &[u8]) -> Option<usize> {
                         return Some(cursor);
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -9164,9 +9148,7 @@ pub fn html_block_start(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -10279,9 +10261,7 @@ pub fn html_block_start_7(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -10509,9 +10489,7 @@ pub fn setext_heading_line(s: &[u8]) -> Option<SetextChar> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -10845,9 +10823,7 @@ pub fn footnote_definition(s: &[u8]) -> Option<usize> {
                 17 => {
                     return Some(cursor);
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -11690,9 +11666,7 @@ pub fn scheme(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -12735,9 +12709,7 @@ pub fn autolink_uri(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -16586,9 +16558,7 @@ pub fn autolink_email(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -17635,9 +17605,7 @@ pub fn html_tag(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -18030,9 +17998,7 @@ pub fn html_comment(s: &[u8]) -> Option<usize> {
                 15 => {
                     return Some(cursor);
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -18559,9 +18525,7 @@ pub fn html_processing_instruction(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -18868,9 +18832,7 @@ pub fn html_declaration(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -19347,9 +19309,7 @@ pub fn html_cdata(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -19411,9 +19371,7 @@ pub fn spacechars(s: &[u8]) -> Option<usize> {
                 3 => {
                     return Some(cursor);
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -20588,9 +20546,7 @@ pub fn link_title(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -21372,9 +21328,7 @@ pub fn dangerous_url(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -21703,9 +21657,7 @@ pub fn table_start(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -22279,9 +22231,7 @@ pub fn table_cell(s: &[u8], spoiler: bool) -> Option<usize> {
                             }
                         }
                     }
-                    _ => {
-                        panic!("internal lexer error")
-                    }
+                    _ => panic!("internal lexer error"),
                 }
             }
         }
@@ -22781,9 +22731,7 @@ pub fn table_cell(s: &[u8], spoiler: bool) -> Option<usize> {
                             }
                         }
                     }
-                    _ => {
-                        panic!("internal lexer error")
-                    }
+                    _ => panic!("internal lexer error"),
                 }
             }
         }
@@ -22846,9 +22794,7 @@ pub fn table_cell_end(s: &[u8]) -> Option<usize> {
                 3 => {
                     return Some(cursor);
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -23000,9 +22946,7 @@ pub fn table_row_end(s: &[u8]) -> Option<usize> {
                         }
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -23102,9 +23046,7 @@ pub fn shortcode(s: &[u8]) -> Option<usize> {
                 7 => {
                     return Some(cursor);
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -23258,9 +23200,7 @@ pub fn open_multiline_block_quote_fence(s: &[u8]) -> Option<usize> {
                         return Some(cursor);
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -23414,9 +23354,7 @@ pub fn close_multiline_block_quote_fence(s: &[u8]) -> Option<usize> {
                         return Some(cursor);
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
-                }
+                _ => panic!("internal lexer error"),
             }
         }
     }
@@ -23840,9 +23778,93 @@ pub fn tasklist(s: &[u8]) -> Option<(usize, u8)> {
                         return Some((cursor, s[t1]));
                     }
                 }
-                _ => {
-                    panic!("internal lexer error")
+                _ => panic!("internal lexer error"),
+            }
+        }
+    }
+}
+
+pub fn description_item_start(s: &[u8]) -> Option<usize> {
+    let mut cursor = 0;
+    let len = s.len();
+
+    {
+        #[allow(unused_assignments)]
+        let mut yych: u8 = 0;
+        let mut yystate: usize = 0;
+        'yyl: loop {
+            match yystate {
+                0 => {
+                    yych = unsafe {
+                        if cursor < len {
+                            *s.get_unchecked(cursor)
+                        } else {
+                            0
+                        }
+                    };
+                    cursor += 1;
+                    match yych {
+                        0x3A | 0x7E => {
+                            yystate = 3;
+                            continue 'yyl;
+                        }
+                        _ => {
+                            yystate = 1;
+                            continue 'yyl;
+                        }
+                    }
+                }
+                1 => {
+                    yystate = 2;
+                    continue 'yyl;
+                }
+                2 => {
+                    return None;
+                }
+                3 => {
+                    yych = unsafe {
+                        if cursor < len {
+                            *s.get_unchecked(cursor)
+                        } else {
+                            0
+                        }
+                    };
+                    match yych {
+                        0x09 | 0x20 => {
+                            cursor += 1;
+                            yystate = 4;
+                            continue 'yyl;
+                        }
+                        _ => {
+                            yystate = 2;
+                            continue 'yyl;
+                        }
+                    }
+                }
+                4 => {
+                    yych = unsafe {
+                        if cursor < len {
+                            *s.get_unchecked(cursor)
+                        } else {
+                            0
+                        }
+                    };
+                    match yych {
+                        0x09 | 0x20 => {
+                            cursor += 1;
+                            yystate = 4;
+                            continue 'yyl;
+                        }
+                        _ => {
+                            yystate = 5;
+                            continue 'yyl;
+                        }
+                    }
+                }
+                5 => {
+                    return Some(cursor);
                 }
+                _ => panic!("internal lexer error"),
             }
         }
     }
diff --git a/src/tests/description_lists.rs b/src/tests/description_lists.rs
index 06970fc0..e2bd23cd 100644
--- a/src/tests/description_lists.rs
+++ b/src/tests/description_lists.rs
@@ -1,7 +1,7 @@
 use super::*;
 
 #[test]
-fn description_lists() {
+fn description_lists_loose() {
     html_opts!(
         [extension.description_lists],
         concat!(
@@ -14,7 +14,7 @@ fn description_lists() {
             ": Definition 2\n"
         ),
         concat!(
-            "<dl>",
+            "<dl>\n",
             "<dt>Term 1</dt>\n",
             "<dd>\n",
             "<p>Definition 1</p>\n",
@@ -41,7 +41,7 @@ fn description_lists() {
             "<ul>\n",
             "<li>\n",
             "<p>Nested</p>\n",
-            "<dl>",
+            "<dl>\n",
             "<dt>Term 1</dt>\n",
             "<dd>\n",
             "<p>Definition 1</p>\n",
@@ -57,6 +57,89 @@ fn description_lists() {
     );
 }
 
+#[test]
+fn description_lists_tight() {
+    html_opts!(
+        [extension.description_lists],
+        concat!(
+            "Term 1\n",
+            ": Definition 1\n",
+            "\n",
+            "Term 2 with *inline markup*\n",
+            ": Definition 2\n"
+        ),
+        concat!(
+            "<dl>\n",
+            "<dt>Term 1</dt>\n",
+            "<dd>Definition 1</dd>\n",
+            "<dt>Term 2 with <em>inline markup</em></dt>\n",
+            "<dd>Definition 2</dd>\n",
+            "</dl>\n",
+        ),
+        no_roundtrip,
+    );
+
+    html_opts!(
+        [extension.description_lists],
+        concat!(
+            "* Nested\n",
+            "\n",
+            "    Term 1\n",
+            "    :   Definition 1\n\n",
+            "    Term 2 with *inline markup*\n",
+            "    :   Definition 2\n\n"
+        ),
+        concat!(
+            "<ul>\n",
+            "<li>\n",
+            "<p>Nested</p>\n",
+            "<dl>\n",
+            "<dt>Term 1</dt>\n",
+            "<dd>Definition 1</dd>\n",
+            "<dt>Term 2 with <em>inline markup</em></dt>\n",
+            "<dd>Definition 2</dd>\n",
+            "</dl>\n",
+            "</li>\n",
+            "</ul>\n",
+        ),
+        no_roundtrip,
+    );
+}
+#[test]
+fn description_lists_edge_cases() {
+    html_opts!(
+        [extension.description_lists],
+        concat!(":"),
+        concat!("<p>:</p>\n"),
+    );
+
+    html_opts!(
+        [extension.description_lists],
+        concat!(": foo"),
+        concat!("<p>: foo</p>\n"),
+    );
+
+    html_opts!(
+        [extension.description_lists],
+        concat!("a\n:"),
+        concat!("<p>a\n:</p>\n"),
+    );
+
+    html_opts!(
+        [extension.description_lists],
+        concat!("- foo\n", "- : bar\n", "  - baz\n",),
+        concat!(
+            "<ul>\n",
+            "<li>foo</li>\n",
+            "<li>: bar\n",
+            "<ul>\n",
+            "<li>baz</li>\n",
+            "</ul>\n",
+            "</li>\n",
+            "</ul>\n",
+        ),
+    );
+}
 #[test]
 fn sourcepos() {
     // TODO There's plenty of work to do here still.  The test currently represents
diff --git a/src/tests/fixtures/description_lists.md b/src/tests/fixtures/description_lists.md
new file mode 100644
index 00000000..5f689014
--- /dev/null
+++ b/src/tests/fixtures/description_lists.md
@@ -0,0 +1,298 @@
+---
+title: Description / defintition lists
+based_on: https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/definition_lists.md
+---
+
+## Definition lists
+
+The term is given on a line by itself, followed by
+one or more definitions. Each definition must begin
+with `:` (after 0-2 spaces); subsequent lines must
+be indented unless they are lazy paragraph
+continuations.
+
+The list is tight if there is no blank line between
+the term and the first definition, otherwise loose.
+
+```````````````````````````````` example
+apple
+:   red fruit
+
+orange
+:   orange fruit
+.
+<dl>
+<dt>apple</dt>
+<dd>red fruit</dd>
+<dt>orange</dt>
+<dd>orange fruit</dd>
+</dl>
+````````````````````````````````
+
+Loose:
+
+```````````````````````````````` example
+apple
+
+:   red fruit
+
+orange
+
+:   orange fruit
+.
+<dl>
+<dt>apple</dt>
+<dd>
+<p>red fruit</p>
+</dd>
+<dt>orange</dt>
+<dd>
+<p>orange fruit</p>
+</dd>
+</dl>
+````````````````````````````````
+
+Indented marker:
+
+```````````````````````````````` example
+apple
+  : red fruit
+
+orange
+  : orange fruit
+.
+<dl>
+<dt>apple</dt>
+<dd>red fruit</dd>
+<dt>orange</dt>
+<dd>orange fruit</dd>
+</dl>
+````````````````````````````````
+
+```````````````````````````````` example
+apple
+
+ : red fruit
+
+orange
+
+ : orange fruit
+.
+<dl>
+<dt>apple</dt>
+<dd>
+<p>red fruit</p>
+</dd>
+<dt>orange</dt>
+<dd>
+<p>orange fruit</p>
+</dd>
+</dl>
+````````````````````````````````
+
+Multiple blocks in a definition:
+
+```````````````````````````````` example
+*apple*
+
+:   red fruit
+
+    contains seeds,
+    crisp, pleasant to taste
+
+*orange*
+
+:   orange fruit
+
+        { orange code block }
+
+    > orange block quote
+.
+<dl>
+<dt><em>apple</em></dt>
+<dd>
+<p>red fruit</p>
+<p>contains seeds,
+crisp, pleasant to taste</p>
+</dd>
+<dt><em>orange</em></dt>
+<dd>
+<p>orange fruit</p>
+<pre><code>{ orange code block }
+</code></pre>
+<blockquote>
+<p>orange block quote</p>
+</blockquote>
+</dd>
+</dl>
+````````````````````````````````
+
+Nested lists:
+
+```````````````````````````````` example
+term
+
+:   1. Para one
+
+       Para two
+.
+<dl>
+<dt>term</dt>
+<dd>
+<ol>
+<li>
+<p>Para one</p>
+<p>Para two</p>
+</li>
+</ol>
+</dd>
+</dl>
+````````````````````````````````
+
+Multiple definitions, tight:
+
+```````````````````````````````` example
+apple
+:   red fruit
+:   computer company
+
+orange
+:   orange fruit
+:   telecom company
+.
+<dl>
+<dt>apple</dt>
+<dd>red fruit</dd>
+<dd>computer company</dd>
+<dt>orange</dt>
+<dd>orange fruit</dd>
+<dd>telecom company</dd>
+</dl>
+````````````````````````````````
+
+Multiple definitions, loose:
+
+```````````````````````````````` example
+apple
+
+:   red fruit
+
+:   computer company
+
+orange
+
+:   orange fruit
+:   telecom company
+.
+<dl>
+<dt>apple</dt>
+<dd>
+<p>red fruit</p>
+</dd>
+<dd>
+<p>computer company</p>
+</dd>
+<dt>orange</dt>
+<dd>
+<p>orange fruit</p>
+</dd>
+<dd>
+<p>telecom company</p>
+</dd>
+</dl>
+````````````````````````````````
+
+Lazy line continuations:
+
+```````````````````````````````` example
+apple
+
+:   red fruit
+
+:   computer
+company
+
+orange
+
+:   orange
+fruit
+:   telecom company
+.
+<dl>
+<dt>apple</dt>
+<dd>
+<p>red fruit</p>
+</dd>
+<dd>
+<p>computer
+company</p>
+</dd>
+<dt>orange</dt>
+<dd>
+<p>orange
+fruit</p>
+</dd>
+<dd>
+<p>telecom company</p>
+</dd>
+</dl>
+````````````````````````````````
+
+
+
+`~` may be used as a marker instead of `:`:
+
+```````````````````````````````` example
+apple
+  ~ red fruit
+
+orange
+  ~ orange fruit
+.
+<dl>
+<dt>apple</dt>
+<dd>red fruit</dd>
+<dt>orange</dt>
+<dd>orange fruit</dd>
+</dl>
+````````````````````````````````
+
+Definition terms may span multiple lines:
+
+```````````````````````````````` example
+a
+b\
+c
+
+:   foo
+.
+<dl>
+<dt>a
+b<br />
+c</dt>
+<dd>
+<p>foo</p>
+</dd>
+</dl>
+````````````````````````````````
+
+Definition list with preceding paragraph
+(<https://github.com/jgm/commonmark-hs/issues/35>):
+
+```````````````````````````````` example
+Foo
+
+bar
+:   baz
+
+bim
+:   bor
+.
+<p>Foo</p>
+<dl>
+<dt>bar</dt>
+<dd>baz</dd>
+<dt>bim</dt>
+<dd>bor</dd>
+</dl>
+````````````````````````````````